Methylcobalamin is the best absorbed type for the best results.
Sub-lingual- or not, is a controversy, but I take it under the tongue.
Jarrow is a good brand. I use 1000-2000mcg (1-2 mgs) per day.
I find it very economical at 'iHerb' (www.iherb.com) when I buy
4 or more bottles of 100 lozenges ea. - less than $8 a bottle.
(7-8 cents ea). I also buy other suppliments at good prices at the same time and get free shipping.